Maize has many valuable characteristics as a summer crop for New Zealand dairy farmers, but the one thing that it doesn't have is big, broad leaves that quickly create a canopy.
Why is this important? Because it means more opportunity for sunlight to reach bare ground between newly emerged maize seedlings than would be the case if you were growing broadleaf forage species like turnips, or fodder beet.
Sunlight plus bare ground plus relatively narrow maize leaves adds up a to a big competitive advantage for weeds.
And since most maize crops are planted at 76cm row spacings, there's also plenty of empty space for weeds to flourish in the early stages of establishment.
Pre-emergence weed control is always the foundation of a healthy maize crop. But sometimes you need post-emergence herbicides too, to make sure crop yield is not impacted by weed competition before the canopy closes over.
Several post-emergence herbicides are available, depending on what kind of weeds you need to control.
Nufarm Territory Manager Jason Marriott says one useful option is a tank mix of Latro® WG, Primiera® and Bonza®. "It's a versatile mix that works very well. It gives growers control of one of the widest weed spectrums of any combination for broadleaf and grass weeds in the market, particularly on long-term maize ground where tough perennial weeds can be a challenge."
Latro is essentially a grass weed herbicide with some activity on broadleaf weeds, while Primiera is a broadleaf herbicide with some activity against grass weeds, Jason explains.
"Combined, they give the best level of weed control we've seen in maize, including problem weeds like Amaranthus species, black nightshade, fathen and yellow bristle grass."
Grass weeds controlled by Latro WG include couch, ryegrasses, kikuyu, Mercer grass and annual grass weeds such as barnyard grass, bristle grasses, crowfoot grass, smooth witchgrass and summer grass.
Other broadleaf weeds controlled by Primiera include chickweed, spurry, mallow, clover, willow weed, wire weed and seedling docks. Primiera also has activity against atrazine-resistant fathen.
Application timing is important. Nufarm Technical Specialist Paul Addison advises growers to make sure they spray before maize plants reach 50cm in height to avoid crop injury.
Latro, Primiera and Bonza should not be applied to sweetcorn or popcorn.
For more information about successful post-emergence weed control in your maize grain or silage crops this season, talk to your local Technical Sales Rep or visit your Farm Source Store.
® Latro is a registered trademark of Nufarm Australia Limited.
® Primiera and Bonza are registered trademarks of Nufarm Limited.